1. Field of the Invention
The present invention relates to a photographic printer, and particularly relates to a photographic printer in which an exposure device for controlling exposure for a photosensitive member is improved.
2. Description of the Prior Art
Conventionally, photographic printers in which a laser, a liquid crystal shutter, or an LED array is used as an exposure device have been superior to other printers in printing speed and in height of resolution of the photographic printer, and reduction in size as well as in cost of the photographic printers have been eagerly expected. The photographic printer having an exposure device which employs such an LED array, a liquid crystal shutter, or the like, is considered to have a bright future because of its features that the printer has no movable portion in the structure of the exposure device and therefore the photographic printer is stable in operation compared with the laser printer and that there is no problem in the rising time required for a rotary system until the printer is enabled to start, etc.
In the photographic printer, however, it is necessary to make all the elements in the LED array or liquid crystal shutter even in light quantity and to improve the degree of integration of the elements, in order to improve the resolution of the photographic printer. In the photographic printer in which an LED array is used, it is required to connect a plurality of LED tips in which numbers of LED elements are integrated, and therefore it is necessary to perform light quantity correction for every LED element or for every LED tip, resulting in increase in cost of LED array modules.